Orbital Floor (Blowout) Fracture

Introduction

Fractures of the orbital floor and medial orbital wall (blowout fractures) are common midface injuries.

Orbital fractures have a distinct trauma mechanism and are complex, due to the complex anatomy of the bony and soft tissue structures involved.

Knowledge of anatomy is mandatory when dealing with patients presenting with trauma to the orbit.

The frontal, ethmoidal, sphenoid, zygomatic, and lacrimal bones form the bony structures of the orbit. Medially, the maxillary and the lacrimal bone form the lacrimal fossa. Together with the lamina papyracea of the ethmoid bone, they form the medial wall. The sphenoid bone forms the posterior wall and houses the orbital canal. Lateral to the orbital canal lies the superior orbital fissure housing cranial nerves III, IV, V, and VI. The zygomatic bone forms the lateral wall. Superior and inferior borders are the frontal and maxillary bone. Located around the globe of the eye and attached to it are 6 extraocular muscles; the 4 rectus muscles and the superior and inferior oblique muscles. The fat and connective tissue around the globe help to reduce the pressure exerted by the extraocular muscles.[1][2]

Etiology

A blowout fracture is an isolated fracture of the orbital walls without compromise of the orbital rims.[3] The common mechanisms are falls, high-velocity ball-related sports, traffic accidents, and interpersonal violence.

The trauma mechanism is a blunt, directed force which may be aimed at the eye, without a pressure component toward the eye rim leading to an increase of pressure inside the orbit with a fracture of the bony structures (hydraulic mechanism). Alternatively, the trauma may be directed towards the orbital rim, which then leads to a bending of the orbital walls with consequent fracturing (buckling mechanism).[4][5]

The mechanism of entrapment is more frequently referred to as a trapdoor in children, as opposed to the "blowout or punched-out" fracture present in adults.

Epidemiology

Orbital fractures are more common in males than in females and most often occur in men, ages 21 to 30 years of age.[6]

Fractures of the orbital floor and the medial orbital wall are the most common fractured site.[7]

History and Physical

Modern imaging techniques do not replace history and physical examination. The physical examination is especially important to help distinguish between fractures that need acute surgical care and referral versus those for which simple observation is sufficient. Some patients present with extensive damage to other facial structures for which detailed assessment is mandatory. Some limitations may exist due to extensive soft tissue swelling or non-responsive patients.

Traumatized patients should be treated only after the initial assessment, according to advanced trauma life support criteria. Examination always has to include a full examination of the facial structures according to current guidelines published by the relevant authority.

The patient should be queried specifically about the trauma mechanism and if he/she has double vision, numbness to his face and/or loss of visual acuity.

The following assessments are characteristic of orbital floor fractures and mandate further imaging:

Diplopia (on upward gaze)

Limitation of upward gaze

Trigeminal function assessment: The infraorbital nerve runs along the floor of the orbit. decreased sensation over the inferior orbital rim, extending to the edge of the nose and ipsilateral upper lip.

Tenderness, or step-offs at the infraorbital rim

Subcutaneous emphysema (indicates fracture of the maxillary sinus)

Oculomotor function: Entrapment of the inferior rectus muscle; often occurs between fragments of the lower orbit and is the cause of diplopia

Pupillary light reflex: An absent reflex can show damage to the afferent or efferent nerve system

Gross visual acuity

Position of the globe: A dislocated fracture can lead to enophthalmos and swelling behind the globe, to exophthalmos

Carefully evaluation of the eye is important for visual acuity, hyphema, or retinal detachment, and of the nose, for septal hematoma. In the presence of eye pain and decreased visual acuity, globe rupture should be suspected, since it is associated with a high rate of concomitant orbital floor fracture.

Evaluation

CT Scan

Computed tomography is the imaging modality of choice if a blowout fracture is suspected after blunt orbital trauma. Some symptoms include double vision, pain with eye movements, and restriction of extraocular muscle movements. A CT scan often reveals herniation of orbital fat or the inferior rectus muscle, into the maxillary sinus. Such a scan can also detect occult tears and retained foreign bodies if any are present.

Plain Radiograph

Can help suspect an orbital floor fracture in the presence of the following:

Subcutaneous emphysema

Soft-tissue teardrop along the roof of the maxillary sinus

Air-fluid level in the maxillary sinus

Treatment / Management

The choice of orbital fracture treatment depends on findings following a clinical examination. Indications for surgery vary among different countries; but, there is a consensus about several indications for surgery.

However, considerable differences in opinion may exist regarding the management of blowout fracture due to a lack of a reliable consensus. Nonetheless, early surgical intervention (preferably within 24 hours) is necessary when other injuries threaten the eye such as nerve incarceration, acute enophthalmos or hypoglobus, and limitation of gaze caused by extraocular muscle or periorbital tissue entrapment. Many clinicians have recommended that orbital volume increases be treated, as an indication for early reconstructive surgery. However, the increased post-traumatic orbital volume is not particularly useful in predicting late enophthalmos or diplopia.

Entrapment of muscle or periorbital fat which leads to diplopia and/or initiation of the oculocardiac reflex with bradycardia, nausea, and vomiting. These can be life-threatening and indicate a need for immediate surgery.[12]

Retrobulbar hematoma with a progressive loss in visual acuity

Enophthalmos on first clinical examination

Relative indications for surgery are high-risk fractures for enophthalmos, which involve over one-half of the orbital floor or lateral orbital wall.[13]

Use an observation with possible intervention within 1 to 2 weeks in all other cases of confirmed orbital floor fractures.[14]

Patients with fractures where the orbital floor fragments are not displaced, and the orbital volume remains unchanged, can be addressed without any surgical intervention.

The goal of surgery is to restore herniated structures into the orbital cavity.

Relative contraindications for surgery according to Kim et al. include the following conditions:

Begin prophylactic antibiotic treatment for any oral organisms in all types of fractures of the orbit.

Differential Diagnosis

Imaging should provide useful information to differentiate orbital floor fractures from any of the following:

Medial or lateral wall fractures

Orbito-zygomatic fractures

LeFort I, II, and III fractures

Naso-orbital ethmoidal fractures (Markowitz fractures)

Clinical examination has to eliminate the need for acute intervention under the following conditions:

Large fractures with a high risk of enophthalmos

Entrapment of infra-orbital structures

Optical neuropathy

Complications

Acute surgical complications include loss of vision due to retrobulbar hematoma or impingement of the orbital apex.

Delayed surgical complications depend on the surgical procedure used and include entropion, ectropion, diplopia, infraorbital paresthesia, enophthalmos, and blindness.

Postoperative and Rehabilitation Care

During postoperative care, the examiner should watch out for postoperative complications such as infection, visual, or central nervous system (CNS) symptoms.

Pearls and Other Issues

Diplopia with upward gaze, limited upward gaze, infraorbital anesthesia, and enophthalmos are hallmarks of blow-out fractures and need a referral for surgical evaluation. However, initial clinical presentation is not always able to predict long-term sequelae, such as late enophthalmos and diplopia.

Early ophthalmologic consultation is mandatory

Observation of uncomplicated fractures is recommended for a period of up to 2 weeks; then a decision can be made whether the patient needs surgery.

Loss of vision, exophthalmos, and absent pupillary light reflex are important criteria for ruling out optic neuropathy.

Enhancing Healthcare Team Outcomes

An interprofessional approach to blow-out fracture is recommended.

Management is relevant from a number of surgical specialties, such as otolaryngological (ENT) surgery, plastic surgery, facial plastic surgery, ocular plastic surgery, and oral maxillofacial surgery.

Ophthalmologist: All patients suspected of orbital fractures must see an ophthalmologist on presentation to the emergency department and before surgery

Monitoring of the patients may be done in the ICU or the surgical floor, depending on the extent of the injury. At all times, the nurse should closely monitor the vitals, Glasgow coma score (GCS) score and assess the patient for mental status changes.

The outcome of most blow out fractures is good, but some patients may have altered eye function and cosmetic changes of the face.[6][16](Level V)